Floating pawl



Feb. 1, 1949. BE CARLSTROM 2,460,620

FLOATING PAWL Filed June 14, 1945 INVENTOR. ELIS 'F. GARLSTROM ATTY.

Patented Feb. 1, 1949 FLOATING PAWL Elis Fedor Carlstrom, Lancaster,Pa., assignor to Hamilton Watch Company, Lancaster, Pa.

Application June 14, 1945, Serial No. 599,354

7 Claims.

This invention relates to a pawl to be used between a pair of meshinggears and is more particularly concerned with a pawl which floatsbetween the gears rather than a pivoted pawl operating on a single gear.

The object of the present invention is to provide a pawl which serves asa stop between a pair of meshing gears.

A further object is to provide a pawl for a pair of gears, which pawl isnot pivoted but floats within the confines of a recess between thegears, being held in place by an extension underlying one of the gears.

A further object of the present invention is to provide a pawl which ismoved into and out of gear contacting position by movement of the gearsthemselves.

A further object is to provide a pawl retained within the confines of arecess underlying one of the gears, the pawl being provided with aspringlike extension engaging the under surface of one of the gears, thefrictional contact moving the pawl into and out of gear engagingposition.

A still further object of the'present invention is to provide a pawlformed with a flat springlike extension underlying one of a pair ofmeshing gears, said springlike extension being provided with an upturnedportion adapted to engage the edge of the teeth of the gears to providea positive action for forcing the pawl into looking position.

With the foregoing and other objects in view, the invention resides inthe novel arrangement and combination of parts and in the details ofconstruction hereinafter described and claimed, it being understood thatchanges in the precise embodiment of the invention herein described maybe made within the scope of what is claimed without departing from thespirit of the invention.

The invention is illustrated in the accompanying drawing in which:

Fig. 1 is a top plan view of the pawl.

Fig. 2 is a side view of the same.

Fig. 3 is a partial view of the pawl as applied to the winding gears ofa watch mechanism, showing the pawl in looking position.

Fig. 4 is a similar view showin the pawl in position during the windingof the watch.

Fig. 5 is a composite view showing the pawl in looking position in fulllines and in free position in dotted lines, the free position showingthe upturned portion adapted to be engaged between each of the teeth.

Referring in detail to the drawings a pillar plate I of a watchmechanism is shown having 2 a crown to a winding stem 3, a winding gearand a mains-pring gear 5, Gears 4 and 5 are set in recesses 6 and!milled in the pillar plate I. Slightly below the lever of the recesses 6and 1 an elongated shaped recess 8 is milled to receive a pawl 9.

The pawl 9 is formed with a fiat body portion Ill split at H and formedwith an integral lip l2 havin a tooth engaging spur l3 and a riding edgeit. On the body portion It! the split llextends to the riding edge l4forming a narrow spring finger 15 which projects slightly above thesurface In to form a tooth engaging edge 16. The back end of the bodyportion I0 is rounded as at IT to conform to the curve l8 of the milledrecess 8.

The operation of the pawl, which is carried in a milled recess 8 andbeneath the gear 5, and because of the depth of the recess 8 hasfrictional contact with the gear 5,'freely floating within the confinesof the recess, is shown in Fig. 3 for locking, and in Fig. 4 for freewinding of the watch. Referring to Fig. 4, the pawl is shown in itsuppermost position, at which time it is disengaged from the gears 4 and5. The frictional contact between the spring finger or strip H and theundersurface of gear 5 is suilicient to move the pawl to the positionshown in Fig. 4 immediately with the turning of gear 5. The distancewhich the spur point I3 is moved away from the teeth 19 of the gear 4during disengagement is very important as this determines the backmovement of the gears 4 and 5 previous to being held by the pawl, Thisis particularly important as it prevents too tight winding of themains'pring.

Referring to Fig. 3 the pawl is shown in the position which it will takeupon the release of the winding moment and the tendency of the gear 5 toturn in the direction of the arrow shown in Fig. 3 under the influenceof the mainspring. This tendency of gear 5 to turn counterclockwiseunder the influence of the mainspring moves the pawl by its frictionalcontact into the position shown in Fig. 3, allowing the gears tobacktrack a distance of approximately two teeth before looking. This isknown as recoil action.

Referring particularly to Fig. 5 the position of the pawl with relationto the teeth of the gear 5 is shown, the edge l6 of the pawl engagingthe edge of the teeth 20 of the gear 5, thus assuring positive action ofthe pawl should the frictional contact be too slight to throw the pawlinto locking position. It must be realized that this is an extremelysmall piece of mechanism and the spring tension on the finger I5 isextremely -slight although sumcient to insure the positive working ofthe pawl.

What is claimed is:

1. In a winding mechanism, a pair of meshing gears, a pawl formed withan elongated flat portion adapted to underlie one of the gears, anupstanding wedge shaped portion adapted to be moved into and away fromlocking position through frictional contact between the flat surthegears.

2. In a winding mechanism, a pair of meshing upstanding wedge shapedportion adapted to be moved into and away from looking position befaceof the'pawl and the undersurface of one of gears, a pawl formed with anelongated flat =por- -tion adapted to underlie one of the gears, an

tween said gears, said flat portion having in-* tegral therewith aspring finger projecting slight-'- 1y above the surface of said flatportion to provide irictional contact between the undersurface atone or.said gears and the flat surface of the 7 3., In. a winding mechanism, apair of meshing gears, apawl formed with an elongated fiat portionadapted to'underlie one of said gears, an upstanding wedge-shapedportion being formed with a. gear riding surface and a gear engagingspur, means integral with said fiat surface and projecting slightlyabove said fiat surface to engage the underside of one of said gears,whereby the pawl is moved into'and out of locking position throughrotational movement of the gear. r

4.111 a watch movement, a pillar plate formed to receive a pairoimeshing gears and also formed with a recess extending under saidgears, a pawl having an elongated flat portion housed in said milledrecess, said elongated flat portion underlying one of said gears, thepawl movable freely within thelconfines of said recess and a springextension formed integral with said elongated flat portion and extendingslightly above the surface of said elongated flat portion to provideirictionalcontact between the pawl and the undersurface of one of saidgears, whereby the pawl is moved into and out of locking engagement withthe gears.

5. In a watch movement, a pillar plate having a pair of circularrecesses therein to receive a pair of meshing gears, said pillar platebeing also formed with an elongated recess partially underlying saidgears, a pawl partially housed and restricted in movement by said lastmentioned recess, a certain portion. of. said pawl underlying one of thegears, means carried by said pawl and providing frictional engagementwith the undersurface of one of said gears, whereby movement of thegears swings the pawl into and out of locking engagement with the gears.

6. In a watch movement, a pillar plate formed with a pair of circularrecesses to receive a pair of meshing gears, said pillar plate beingalso formed with an elongated recess partially underlying said meshinggears, a pawl formed with an elongated flat portion and an upstandinggear engaging wedge-shaped portion, said elongated flat portion of thepawl being carried withinsaid recess, the recess restricting themovement of said'pa'wl'to in and out of locking engagement with thegears and means integral with said elongate-d flat portion to providefrictional contact between the pawl and the under-surface of one of saidgears.

7. A pawl formed from a single piece of metal having an elongated fiatportion and an upstanding wedge-shaped portion, said wedge-shapedportion being formed with a gear tooth riding face and a gear engagingspur, said elongated flat portion being formed with an integral springextension to project slightly above the surface of said elongated fiatportion.

ELIS FEDOR CARLSTROM.

REFERENCES CITED "The following references are of record in the file ofthis patent:

FOREIGN PATENTS Country Date

